Rotary engines such as the ones known as Wankel engines use the eccentric rotation of a piston to convert pressure into a rotating motion, instead of using reciprocating pistons. In these engines, the rotor includes a number of apex portions which remain in contact with a peripheral wall of the rotor cavity of the engine throughout the rotational motion of the rotor.
The eccentric rotary motion of the rotor is guided through a rotor phasing gear which is meshed with a stator phasing gear. The rotor phasing gear is typically made of a different material than a remainder of the body of the rotor, and as such is usually manufactured separately therefrom. It is known to attach the phasing gear to the rotor body through fasteners located on the outer diameter of the phasing gear.